https://blog.jayway.com/2013/06/20/dont-publish-domain-events-return-them/

https://lostechies.com/jimmybogard/2014/05/13/a-better-domain-events-pattern/

http://udidahan.com/2009/06/14/domain-events-salvation/

https://en.wikipedia.org/wiki/Immutable_object

https://martinfowler.com/eaaDev/EventSourcing.html

http://www.infoq.com/cn/articles/implementation-road-of-domain-driven-design/

https://en.wikipedia.org/wiki/Event-driven_architecture